In one aspect, the invention relates to the separation of the components of a gas stream. In another aspect, the invention relates to the separation of a high purity stream of hydrogen gas from a gas stream. In still another aspect, the invention relates to the separation and recycling of a high purity hydrogen stream from and to a hydroretort.
"Hydroretorting" is retorting which is conducted in the presence of added hydrogen. Retorting is one method by which carbonaceous material, especially oil shale, can be upgraded to more valuable predominantly liquid hydrocarbon products. It has been found that conducting the retorting of certain oil shales in the presence of added hydrogen provides increased yield and product quality.
To promote the thermal efficiency of the retorting process, it is desirable to combust residual carbon from the retorted shale using oxygen containing gas to provide the heat for driving the retorting process. Leakage of combustion products from the combustion zone to the retorting zone results in combustion products being recovered from the retorting zone. The presence of combustion products such as carbon monoxide causes problems in the purification and recycling of hydrogen to the retort.
Hydrogen recovery is more important in a hydroretorting process than is common for many hydrogen purifiers because the hydroretorting process is a large consumer of hydrogen. Any loss of hydrogen must be made up by converting hydrocarbon retort product to hydrogen and carbon dioxide, an expensive process.